Flovent Inhaler

- High-volume, Low-pressure Cuffs (11)

High-volume, Low-pressure Cuffs (11)By increasing its intracuff (hence CT) pressure, the cuff is automatically compensating for the increases in airway pressure without additional inflation. This self-sealing action was described by Carroll et al who wrote.. we discovered in 1968 that any large diameter, large residual volume cuff can be inflated to a baseline pressure just adequate to prevent aspiration, and that this resting intracuff pressure then rises in synchrony with the airway pressure.”
The self-sealing nature of large volume cuffs is explained by the dynamic effects of airway pressure on cuff size and shape. Increasing airway pressure is freely transmitted to the cuff across the flexible cuff wall, equalizing intracuff pressure and airway pressure. As airway pressure continues to rise, the gas contained within the cuff moves away from the area of high pressure (the distal cuff) and toward an area of lower pressure (the proximal cuff). Thus, the gas within the cuff is redistributed, or “milked” from the distal end of the cuff to fill the proximal end, resulting in a cone-shaped cuff (Fig 3) as the cuff collapses distally and bulges proximally. In 1971 Lomholt described “… this transformation of the cuff shape from cylindrical to conical during the inspiratory phase.. and estimated the extent to which such cuffs could compensate for volume changes while maintaining their seal.

June 18, 2013 Cardiac function
Tags: airway pressure ischemic tracheal complications tracheal stenosis